Proposal of a Network-Based Minority Game Model with Observation and Modification Processes (original) (raw)

Minority game with communication: an agent based model

2004

ABSTRACT The Minority Game (MG) is a simple, generalized framework, belonging to the Game Theory field, which represents the collective behaviour of agents in an idealized situation where they have to compete through adaptation for some finite resource. it generalizes the study of how many individuals may reach a collective solution to a problem under adaptation of each one's expectations about the future.

Properties of interaction networks underlying the minority game

Physical Review E, 2014

The Minority Game is a well known agent-based model with no explicit interaction among its agents. However, it is known that they interact through the global magnitudes of the model and through their strategies. In this work we have attempted to formalize the implicit interactions among Minority Game agents as if they were links on a complex network. We have defined the link between two agents by quantifying the similarity between them. This link definition is based on the information of the instance of the game (the set of strategies assigned to each agent at the beginning) without any dynamic information on the game, and brings about a static, unweighed and undirected network. We have analyzed the structure of the resulting network for different parameters, such as the number of agents (N) and the agent's capacity to process information (m), always taking into account games with two strategies per agent. In the region of crowd-effects of the model, the resulting networks structure is a small world network, whereas in the region where the behavior of the Minority Game is the same as in a game of random decisions, networks become a random network of Erdos-Renyi. The transition between these two types of networks is slow, without any peculiar feature of the network in the region of the coordination among agents. Finally, we have studied the resulting static networks for the Full Strategy Minority Game model, a maximal instance of the Minority Game in which all possible agents take part in the game. We have explicitly calculated the degree distribution of the Full Strategy Minority Game network and, on the basis of this analytical result, we have estimated the degree distribution of the Minority Game network, which is in accordance with computational results.

The Minority Game with interactions

Physica A: Statistical Mechanics and its Applications, 2004

We partially modify the rules of the Minority Game (MG) by introducing some degree of local information in the game, which is only available for some agents, called the interacting agents. Our work shows that, for small values of the new parameter of the model (the fraction of interacting agents), there is an improvement of the use of the resources with respect to the MG, while as this number grows the response of the system changes, and ends up behaving worst than the usual MG.

Emergent cooperation amongst competing agents in minority games

Physica A: Statistical Mechanics and its Applications, 2011

We study a variation of the minority game. There are N agents. Each has to choose between one of two alternatives everyday, and there is reward to each member of the smaller group. The agents cannot communicate with each other, but try to guess the choice others will make, based only the past history of number of people choosing the two alternatives. We describe a simple probabilistic strategy using which the agents acting independently, can still maximize the average number of people benefitting every day. The strategy leads to a very efficient utilization of resources, and the average deviation from the maximum possible can be made O(N ǫ), for any ǫ > 0. We also show that a single agent does not expect to gain by not following the strategy.

Effects of diversity on multiagent systems: Minority games

Physical Review E, 2005

We consider a version of large population games whose agents compete for resources using strategies with adaptable preferences. The games can be used to model economic markets, ecosystems or distributed control. Diversity of initial preferences of strategies is introduced by randomly assigning biases to the strategies of different agents. We find that diversity among the agents reduces their maladaptive behavior. We find interesting scaling relations with diversity for the variance and other parameters such as the convergence time, the fraction of fickle agents, and the variance of wealth, illustrating their dynamical origin. When diversity increases, the scaling dynamics is modified by kinetic sampling and waiting effects. Analyses yield excellent agreement with simulations.

Minority Rule Applied to Multiple Agents Linked into a Social Network with Communication and Memory

2004

In our work we simulate a community of agents, linked into a simple social network based on communication among the nodes, who must take a binary decision at every step. This resembles the original Minority Game (MG), which is a simple, generalized framework, belonging to the Game Theory field, which represents the collective behaviour of agents in an idealized situation where they have to compete through adaptation for some finite resource. It generalizes the study of how many individuals may reach a collective solution to a problem under adaptation of each one’s expectations about the future. The main differences between this work and the original MG are the introduction of communication among the agents, which are now grouped basing on the common choices, and the number of players, that can also be an even number, while in the MG must be an odd number. This is done in order to generalize as much as possible the study of the choices made by agents trying to be in the minority grou...

Chapter VIII Introducing Social Issues into a Minority Game by Using an Agent Based Model

2008

In this chapter, the authors perturb a Minority Game (MG) with some sociological issues, first by imple - menting a social network among the involved agents, through which they can somehow communicate their decision to a group of "friends," a local subset of those participating the game. Thus, the emergent aggregate behaviour will be very far from that of the original MG; the stress here is on the possibility of an agent changing his or her own decision, after getting the information from other n agents. Two different communication protocols among the agents will be examined: a synchronous one and the more realistic asynchronous one. Additionally, in some experiments a memory is introduced, acting as a selec- tion mechanism. Last, some special agents ( Opinion Leaders) whose influence over the others is higher than normal, are implemented in order to study how this can change the aggregate results.

Continuous transition of social efficiencies in the stochastic-strategy minority game

Physical Review E, 2012

We show that in a variant of the Minority Game problem, the agents can reach a state of maximum social efficiency, where the fluctuation between the two choices is minimum, by following a simple stochastic strategy. By imagining a social scenario where the agents can only guess about the number of excess people in the majority, we show that as long as the guess value is sufficiently close to the reality, the system can reach a state of full efficiency or minimum fluctuation. A continuous transition to less efficient condition is observed when the guess value becomes worse. Hence, people can optimize their guess value for excess population to optimize the period of being in the majority state. We also consider the situation where a finite fraction of agents always decide completely randomly (random trader) as opposed to the rest of the population that follow a certain strategy (chartist). For a single random trader the system becomes fully efficient with majority-minority crossover occurring every two-days interval on average. For just two random traders, all the agents have equal gain with arbitrarily small fluctuations.

The underlying complex network of the Minority Game

2008

We study the structure of the underlying network of connections in the Minority Game. There is not an explicit interaction among the agents, but they interact via global magnitudes of the model and mainly through their strategies. We define a link between two agents by quantifying the similarity among their strategies, and analyze the structure of the resulting underlying complex networks as a function of the number of agents in the game and the value of the agents' memory, in games with two strategies per player. We characterize the different phases of this system with networks with different properties, for this link definition. Thus, the Minority Game phase characterized by the presence of crowds can be identified with a small world network, while the phase with the same results as a random decision game as a random network. Finally, we use the Full Strategy Minority Game model, to explicitly calculate some properties of its networks, such as the degree distribution, for the same link definition, and to estimate, from them, the properties of the networks of the Minority Game, obtaining a very good agreement with its measured properties.

Network evolution based on minority game with herding behavior

The European Physical Journal B, 2010

The minority game (MG) is used as a source of information to design complex networks where the nodes represent the playing agents. Differently from classical MG consisting of independent agents, the current model rules that connections between nodes are dynamically inserted or removed from the network according to the most recent game outputs. This way, preferential attachment based on the concept of social distance is controlled by the agents wealth. The time evolution of the network topology, quantitatively measured by usual parameters, is characterized by a transient phase followed by a steady state, where the network properties remain constant. Changes in the local landscapes around individual nodes depend on the parameters used to control network links. If agents are allowed to access the strategies of their network neighbors, a feedback effect on the network structure and game outputs is observed. Such effect, known as herding behavior, considerably changes the dependence of volatility σ on memory size: it is shown that the absolute value of σ as well as the corresponding value of memory size depend both on the network topology and on the way along which the agents make their playing decisions in each game round.